Prunus Tree Rootstock named ‘Piku 4’

ABSTRACT

A new and distinct  Prunus  rootstock compatible with other  Prunus  varieties and producing trees with reduced growth, suitable to sandy soil with high productivity.

Classification: Prunus L.

Varietal denomination: ‘Piku 4’.

BACKGROUND OF THE INVENTION

The present invention comprises a new and distinct cultivar of hybridPrunus known by the varietal name ‘Piku 4’. The new variety wasdiscovered in 1976 in a selective breeding program designed to producegrowth reducing rootstock for cherry trees in Dresden-Pillnitz, Germanyas a cross between an unnamed, unpatented variety of Prunus cerasus(Schattenmorelle) (female parent) and an unnamed, unpatented variety ofPrunus “Kursar” (P. kurilensis×P. sargentii) (male parent). The newvariety differs from its parents in its growth habit. The followingcharacteristic distinguish the new variety from Prunus avium rootstockvarieties:

-   -   1. Three-way hybrid.    -   2. Reduces growth in grafted varieties by 30-40%.    -   3. Suitable for sandy soil.    -   4. Precocious crop.    -   5. Glossiness of upper leaf surface.    -   6. Growth habit.

The new variety was first asexually reproduced via green cuttings in1980 in Dresden-Pillnitz, Germany and subsequent propagation therein hasconfirmed that the characteristics of the new variety are stable and aretransmitted to subsequent generations.

DESCRIPTION OF THE DRAWING

The accompanying photographic drawings illustrate the new variety, withthe color being as nearly true as is possible with color illustrationsof this type.

FIG. 1 shows the tree of the new variety;

FIG. 2 shows a branch with leaves; and

FIG. 3 shows a branch with flower buds;

DESCRIPTION OF THE PLANT

The following detailed description sets forth the characteristics of thenew cultivar. The data which defines these characteristics werecollected by asexual reproductions via green cuttings carried out inDresden-Pillnitz, Germany. The color designations were taken outdoors inDresden-Pillnitz, Germany. Rootstocks were 6 to 7 years old whendescribed. Color designations are noted with reference to standard P.avium rootstock. The new variety prefers dry or sandy soil and is freeof PNRV and PDV. As a rootstock, it can be reproduced via softwoodcuttings or tissue culture. The new variety anchors adequately with someroot sprouts, sufficient compatibility with grafts and exhibits dwarfgrowth vigor.

TREE

-   Size: Small-medium; having an average height of 1.90 m and an    average width of 2.00 m.-   Form: Bushy, drooping.-   Trunk:    -   -   Surface texture.—Smooth.        -   Bark color.—Dark.        -   Diameter.—5.0 cm, measured at a height of 40 cm.-   Branches:    -   -   Surface texture.—Smooth.        -   Bark color.—200A.        -   New growth color.—Light red.        -   Mature growth color.—Brown.        -   Average crotch angle.—60-80°.        -   Internode length.—Medium.        -   Lenticels.—Diameter: 0.05-0.15 cm. Color: 161A. Amount per            shoot: >100.        -   Bud.—Medium, round.-   Leaves:    -   -   Length.—10.4 cm.        -   Width.—5.0 cm.        -   Surface texture.—Upper side glossy.        -   Form.—Elongated, elliptical.        -   Color.—Upper Surface: 146A. Lower Surface: 146B.-   Petioles:    -   -   Length.—1.7 cm.        -   Thickness.—0.15 cm.-   Leaf glands:    -   -   Quantity.—1-4.        -   Position.—Under leaf end.        -   Size.—0.20 cm.        -   Color.—Green-red.-   Stipules:    -   -   Length.—1.0-1.2 cm.-   Flowers:    -   -   Diameter.—2.50 cm.        -   Color.—Upper Surface: N155A. Lower Surface: N155A.        -   Number.—Many.        -   Petals.—Length: Approximately 1.2 cm. Width: Approximately            0.8 cm. Quantity per flower: 5.        -   Sexual characteristics.—Triploid, crop is rare.        -   Stamen number.—>10.        -   Pistil number.—1.

FRUIT

-   Maturity date/location: Mid-season in Dresden, Pillnitz.-   Weight: 2 grams.-   Axial diameter: 1-2 cm.-   Fruit stone:    -   -   Length.—Approximately 0.6 cm.        -   Diameter.—Approximately 0.5 cm.-   Skin: 187A.-   Flesh color: 187A.

GENERAL

-   Weather hardiness: Sufficient tolerance to winter frost.-   Disease resistance: Tolerance to Cytospora.

1. A new and distinct variety of Prunus rootstock named ‘Piku 4’substantially as shown and described.